Stage 3 Forces and Magnetism Comprehension (PDF)

STAGE 3 Unit focus: Forces And Magnetism Text focus: Information Text What Is Magnetism? Magnets are all around us. You have probably been using them since you were a small child....

STAGE 3 Unit focus: Forces And Magnetism Text focus: Information Text What Is Magnetism? Magnets are all around us. You have probably been using them since you were a small child. You might not have realised it at the time, but lots of toys use magnets. Magnets are great for getting things to stick together. When you place plastic le ers onto a whiteboard, and they stay in place, that’s magnetism at work. If you stick something to the fridge, it’s likely to be using a magnet. Those games where you use a small fishing rod to try to collect fish from a tiny pond definitely use magnets. So, isn’t it about time you learned how they work? It turns out that’s a bit more difficult than it might seem. Magnetism is a tricky force. To understand it, we need to zoom in on everything on Earth. Everything around you is made up of atoms. Each atom is far too small to see. They contain lots of particles called electrons. These electrons spin around the atom incredibly quickly. This creates a microscopic electric current, which creates magnetism. This is where it gets even trickier. When an electron spins around, it creates a magnetic field depending on which way it is going. Most materials have electrons spinning in lots of different directions. This means the forces are cancelled out. That’s why things like cloth and paper aren’t magnetic. In some metals, the electrons all spin in the same direction. That’s why iron is magnetic. The Earth is even trickier. It is an enormous magnet. Even the best scientists aren’t entirely sure why the Earth has a magnetic field. The Earth has a liquid core that spins around. Most scientists think that this is generating a magnetic field. This is really interesting because it means that scientists can measure how strong the Earth’s magnetic field has been throughout history. Magma from a volcano contains particles of magnetic rock. A When the magma cools down, the rocks line up with the ding ro Rea und all resources ©2022 Literacy Shed e um C u r r ic ul Th http://www.literacyshedplus.com Earth’s magnetic field. This is exactly the same as a compass needle. By looking at ancient magma, scientists can see how the magnetic field has changed over time. This has led to some startling discoveries. It turns out that the Earth’s magnetic field changes over time. It hasn’t happened very often, but when it does, it means that the North Pole will effectively become the South Pole! This has happened hundreds of times since the Earth was formed. The Earth’s magnetic field is getting weaker at the moment, so it might be happening again. SUMMARY FOCUS 1. How can magnets be useful in toys? 2. Why are some things not magnetic? 3. Why does the Earth have a magnetic field? 4. What strange thing have scientists discovered about the Earth’s magnetic field? VIPERS QUESTIONS R Which part of an atom creates magnetism? R What do scientists use to study the Earth’s magnetic field over time? V Which word describes a discovery as surprising? V Find a word that describes something incredibly small. P What might happen if the Earth’s magnetic field flips? all resources ©2022 Literacy Shed http://www.literacyshedplus.com